Turned on my spare pc this afternoon and was greeted with an AVG shell extension informing me that 'Trojan Horse Backdoor.Agent.BA' had been detected. AVG cannot remove it, and to make matters worse after about 10 seconds the whole system crashes. Naturally this makes it rather difficult to fix.
Running Windows Xp with service pack 1.
If anyone can help with this, I would be very grateful indeed.